The present invention relates to a slide rheostat, and more particularly to improvements in the mounting structure of a leaf spring and a movable insulating plate which are mounted on a for the slide element receiver in order to achieve smooth sliding of the receiver.
As shown in FIG. 1, a prior-art slide rheostat having the aforecited structure is so constructed that a slot 2b is formed in the lengthwise direction of the top of a case 2 fixed to an insulating substrate 1, and a lever 5 extending upwardly from a receiver 4 projects out from the case 2 through the slot 2b. The receiver can be moved in the lengthwise direction of the case 2 by manipulating the lever 5, and a contactor 8a of a slide element 8 is fastened to the underside of the receiver 4 and held in resilient contact with the substrate 1. In order to attain smooth sliding of the receiver 4, slide rheostat are often so constructed with a movable insulating plate 6 urged against the inner surface of the top wall of the case 2 by a leaf spring 7 carried on the upper surface 4a of the receiver 4. The lower 5 extends through the plate 6 and leaf spring 7 and resilient protuberant pieces 7d are disposed at the four corners of the leaf spring 7 in a manner so as to extend upwardly into resilient contact with the movable insulating plate 6. In FIG. 1, symbol 2a indicates screw holes for fixation which are formed in the opposing end parts of the case 2, symbol 4b guide legs which are formed at the four corners of each of the upper and lower surfaces of the slide piece receiver 4, and numeral 3 terminals.
With the prior-art construction, the movable insulating plate 6 and the leaf spring 7 are separate members and must be individually installed on the lever 5 in the assemblage of the slide rheostat. The prior art therefore has the drawbacks of an inferior job efficiency, a complicated management of the components including mixing and the like problems.